チオセミカルバチッド関連化合物の合成 (第5報)

Abstract

Preparation of 2-amino-5-nitro-1, 3, 4-thiadiazole was unsuccessful by the rearrangement of nitro group in the side chaine at 2-position of 2-nitramino-1, 3, 4-thiadiazole and also by direct nitration of 2-acetamido-1, 3, 4-thiadiazole with a mixture of potassium nitrate and conc. sulfuric acid at various temperatures. The reaction of 2-nitramino-5-R-1, 3, 4-thiadiazoles (R=H, CH3, C2H5, C3H7, and iso-C4H9) with benzylamine in boiling xylene afforded 2-benzylamino-5-R-1, 3, 4-thiadiazole (except in the case of R=H) and 3-mercapto-4-benzyl-5-R-4H-1, 2, 4-triazole. The former was also prepared by the reaction of 2-chloro-5-R-1, 3, 4-thiadiazole (R=H, CH3, C2H5, n-C3H7, and iso-C4H9) with benzylamine in methanol. 3-mercapto-4-benzyl-5-R-4H-1, 2, 4-triazoles (R=H, CH3) were prepared from 1-acyl-4-benzyl-3-thiosemicarbazides by cyclization with 10% sodium carbonate solution, which were synthesized by using 80% formic acid, and a mixture of acetic acid and its anhydride with 4-benzyl-3-thiosemicarbazide, respectively. Recation of 4-benzyl-3-thiosemicarbazide with 99% formic acid gave 2-benzylamino-1, 3, 4-thiadiazole.